Sewer

Sewer Maintenance is a division of the City of Hutchinson Public Works Department. The division currently has a staff of 11 people and is responsible for maintaining the sanitary and storm sewer infrastructure systems. There are 4 different general responsibilities involved with maintaining both of the infrastructures:

Responding to customer requests

Construction maintenance

Cleaning maintenance

Inspection (SSES - Sanitary Sewer Evaluation Study)

The division has a fleet of equipment that includes 11 major pieces:

4 Pickups

2 Hydraulic combination sewer cleaners (Vactor is the brand name of equipment)

2 550 gallon flush trucks

1 Dump truck

1 Backhoe

1 CCTV digital color inspection van

Sanitary Sewer Division
This division handles the operation and maintenance of the City's sanitary sewer collection system. Maintenance activities include inspection, cleaning, flushing, and repairs of the approximately 240 miles of sewer lines and over 5,200 manholes. The majority of the city is served by gravity sewer lines ranging in pipe size from 6 to 48 inches in diameter. The majority of the sewer pipes is 8-inch diameter and is typically considered to have a lower volume of water. Sometimes there is not enough water discharged by homes and businesses to keep solids and debris flowing downstream.

The Sewer Maintenance division cleaning crews use the flush trucks to flush water into the sanitary system through the manholes. This process introduces about 500 gallons of water into a sewer line to help move solids and debris. The process also helps locate potential problems or stoppages in the city's sewers before it can affect a building sewer service. The cleaning crews also use Vactors to clean and remove debris from the sanitary sewers. The Vactor can deliver up to 80 gallons of water per minute at a normal operating pressure of 1,500 pounds per square inch. The cleaning crews use the Vactor to clean debris, roots, and grease from the pipe, flush that debris to a manhole, and remove it with very strong suction equipment.

The (SSES) inspection crew has 3 main responsibilities regarding the sanitary sewers:

Enter field data and transfer video inspection data and GPS data into the divisions' data management software. This software organizes infrastructure data, tracks work done on the infrastructure, and provides data that the crews use to update digital GIS maps of the infrastructure. The video equipment the crews use to inspect the sewer pipes digitally formats the color video. The camera can be physically pulled through the sewer lines with cabling or by the Vactor or it can be carried by a self propelled transport unit that has 3 gears, forward, reverse, and neutral. For sewer lines that are 24-inch or larger, the camera is typically carried by a boat that the crews developed. Due to larger volumes of debris and water in these large diameter lines floating the camera is the most practical method for video inspections

The main purpose of the city's storm sewer system is to convey rainwater to ditches, Cow Creek, or the Arkansas River. With the city lying is such a flat area of the Arkansas River basin, maintaining the storm system presents a unique set of challenges. There are approximately 70 miles of storm sewer pipes and well over 3,000 manholes, inlets, and catch basins to maintain. Due to the flatness of the area a reasonable portion of the storm drainage system does not have positive drainage to a ditch, creek, or river. The majority of that portion of the storm system is designed to carry storm water from 1 side of the street to the other through a pipe, alleviating the need for several hundred dips or valley gutters crossing the street.

The construction maintenance crew has 2 main responsibilities:

Repair and replace existing sanitary sewer lines

Repair and replace existing manholes. On occasion, they install short segments of new sanitary sewers for city owned projects. The construction crews apply a wide variety of skills in their job such as operating backhoes and various other dirt moving equipment, shoot grades and elevations, lay brick, pour concrete, carpentry, reading blueprints, using trench shoring equipment, and confined space equipment. Typically point repairs on the sanitary lines can be made by the crew in 1 day. Repairs on the larger lines, lines that require shoring or are deeper than 6 feet, or lines located in close proximity of other buried utilities may complicate the repair/replacement process and take 3 - 5 days or more to complete.

Catch basins and inlets are intended to receive storm water into the system. Unfortunately, these basins and inlets plug when the storm water carries various debris such as sand, dirt, rocks, grass clippings, leaves, sticks, cups, and plastic bags to the inlets and grates. The Sewer Maintenance cleaning crews use the divisions' Vactors to clean and remove debris from the basins and inlets. Dirt, debris, and roots are also removed from the storm pipes with the Vactors.

The SSES crew uses the video equipment to investigate or locate problem areas in the storm pipes that are in need of repair. New storm sewer installed during new street projects is also inspected to assure proper installation procedures were followed.

The construction maintenance crews responsibilities are basically the same as they are for the sanitary sewers... repair and replace existing storm pipe, basin, and inlet infrastructure. The construction crews use their wide variety of skills in the same manner to complete repairs and replacement of storm infrastructure. Using equipment such as backhoes and skid steers, reading blueprints, determining and maintaining grades or elevations, carpentry, laying brick, and pouring concrete are just a few of the skills. For replacement storm basin projects the crews form and pour precast concrete storm basins in house, reducing contract costs.